1. Field of the Invention
The invention relates to a homokinetic joint having an inner hub and an outer hub, in which several tracks assigned to one another in pairs, are provided, in each instance, in which balls guided in a cage are accommodated to transfer a torque between the inner hub and the outer hub, and having a sealing arrangement for sealing the homokinetic joint on at least one side.
2. Description of the Related Art
Such homokinetic joints are used, for example, in longitudinal shafts and side shafts of motor vehicles, and must be provided with a lubricant, before or during installation, which ideally ensures good lubrication over the entire useful lifetime of the homokinetic joint. In order to prevent exit of the lubricant from the joint during operation and, at the same time, penetration of dirt particles or the like, such joints are sealed. Thus, for example, in DE 40 33 275 C2, a rolled or pleated set of bellows is proposed for a rotating homokinetic joint, which set of bellows is attached to a sheet-metal cap with its edge that faces the outer hub of the joint, and mounted on a shaft with its opposite edge, which shaft is connected with the inner hub of the homokinetic joint. Sealing of the joint can therefore only take place during or after assembly of the joint on the shaft. The assembly time for such a joint is thereby increased. Furthermore, it is possible that lubricant exits from the joint before assembly, or that dirt particles penetrate into the joint.
A similar set of bellows is also known from DE 36 03 389 C2, which is held on the outer part of the joint by means of a sheet-metal cap, and has a sleeve packing that rests on the shaft that is connected with the inner part of the joint. In the case of this set of bellows, as well, sealing of the joint is only possible after assembly of the shaft on the inner part of the joint.
A sealing arrangement for an articulated coupling is disclosed in DE 32 27 969 C2, which has a membrane-like sealing cuff. In this connection, the sealing cuff is attached to the outer coupling half by means of a taut band, and lies against a shaft connected with the inner coupling half with its radially inner edge. The sealing arrangement is configured as a membrane-like disk that can have several pleats that run radially.
The homokinetic joints currently being used in motor vehicles are subjected to very high speeds of rotation, in some cases more than 10,000 revolutions per minute. Therefore, high centrifugal forces act on the sealing arrangement, which, together with the high temperatures that occur in the joints, can result in premature failure of the sealing arrangement. Thus it is possible, for example, that a rolled or pleated set of bellows “inflates” at such high speeds of rotation, and bursts. On the other hand, a rolled or pleated set of bellows can also fail because is comes into contact with a pointed or bent region of a sheet-metal cap, for example, or the like, as a result of the centrifugal forces.